#用函数判断质数
def is_prime(n):
    if n < 2:
        return False
    for i in range(2, int(n**0.5) + 1):
        if n % i == 0:
            return False
        return True
if is_prime(100) is True:
    print("此数是质数")
else:
    print("此数不是质数")
#递归实现阶乘
def factorial(n):
    if n == 1:
        return 1
    else:
        return n * factorial(n-1)
print(factorial(5))